U.S. patent number 3,718,764 [Application Number 05/018,571] was granted by the patent office on 1973-02-27 for terminal unit for credit account maintenance system.
This patent grant is currently assigned to Data Coard Corporation. Invention is credited to Raymond J. Deschenes, Robert N. Macdonald.
United States Patent |
3,718,764 |
Deschenes , et al. |
February 27, 1973 |
TERMINAL UNIT FOR CREDIT ACCOUNT MAINTENANCE SYSTEM
Abstract
A system for maintaining an up-to-date record of credit accounts
at a central station includes terminal units at a plurality of
remote stations. Each terminal unit selectively interrogates the
credit account data stored at the central station by transmitting a
message of inquiry regarding the particular account of interest to
the central station. The central station responds to an inquiry
message to access the pertinent data from the account record and to
formulate a reply message advising the inquiring terminal unit of
the status of the account. No inquiry message is transmitted until
the data from which the message is assembled is entered into a data
storage device in the terminal unit. Upon receiving a signal
denoting establishment of a message communication path between the
terminal unit and the central station and a concurrent signal
signifying completion of entry of message data into the storage
device, the terminal unit transmits the inquiry message to the
central station. The reply message from the central station
produces an appropriate visual signal at the terminal unit.
Inventors: |
Deschenes; Raymond J. (Atlanta,
GA), Macdonald; Robert N. (Atlanta, GA) |
Assignee: |
Data Coard Corporation
(Minneapolis, MN)
|
Family
ID: |
21788615 |
Appl.
No.: |
05/018,571 |
Filed: |
March 11, 1970 |
Current U.S.
Class: |
340/5.4;
379/91.01 |
Current CPC
Class: |
G06Q
40/02 (20130101); G06Q 20/4037 (20130101); G07F
7/08 (20130101) |
Current International
Class: |
G06Q
40/00 (20060101); G07F 7/08 (20060101); H04m
011/06 () |
Field of
Search: |
;179/2DP,2R,3,4,2A
;235/61.7B,92 ;340/149A,152 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
IBM Technical Disclosure Vol. 9 No. 2 July 1966 p. 144. Allen, et
al..
|
Primary Examiner: Cooper; William C.
Assistant Examiner: D'Amico; Thomas
Claims
We claim as our invention:
1. A terminal unit for use at a remote station of a data
transmission system having a central station with a data processor
for accessing data from storage records and for formulating coded
messages from the accessed data, said terminal unit comprising:
a memory for storing data,
means for entering data into said memory in accordance with a
proceeding pertaining to a record stored at said central
station,
initiate means operable for proving an initiate signal,
read-out means, effective when activated, for reading out the
contents of said memory in the form of a coded message of inquiry
regarding the status of said record, for transmission to said data
processor at said central station,
dial means responsive to the initiate signal for acquiring a
transmission channel with said central station to transmit said
inquiry message to said data processor and to receive a reply
message thereto from said data processor on said channel,
reply detection means responsive to the contents of said reply
message for visually conveying information at said record,
channel detection means responsive to the establishment of a
transmission channel to said central station only upon the
acquiring of said transmission channel, for activating said
read-out means to transmit said inquiry message,
timing means responsive to the establishment of a transmission
channel to said central station for initiating an interval of
predetermined duration and for generating a decouple signal if a
reply message has not been received at said terminal unit within
the interval,
said dial means responsive to the decouple signal for disconnecting
said terminal unit from said transmission channel,
said memory responsive to the decouple signal to remove the stored
data therefrom.
2. A terminal unit as claimed in claim 1, wherein said reply
detection means is responsive to reception of the reply message
from a central station for providing a valid signal indicative of
the receipt of the reply message, said timing means responsive to
the valid signal for inhibiting the generation of a decouple signal
thereby deactivating said timing means.
3. In a system for investigating the status of credit accounts from
data stored at a central station by the sending of an inquiry
message to the central station and the receiving of the desired
data in the form of a reply message to an inquiry message regarding
a specific credit account, a terminal unit disposed at a station
remote from the central station for transmitting the inquiry
message and for receiving reply messages comprising:
memory means for storing data regarding a particular
proceeding;
entry means for manually entering data into said memory means in
accordance with the proceeding pertaining to a record stored at the
central station;
initiate means operable for providing an initiate signal;
readout means actuatable for reading out the data stored upon said
memory means in the form of an inquiry message and for transmitting
the inquiry message to the central station;
dial means responsive to the initiate signal for acquiring a
transmission channel to the central station;
channel detector means responsive to the establishment of a
transmission channel to the central station for actuating said
readout means to transmit the inquiry message;
reply detection means responsive to the contents of the reply
message from the central station for providing a first signal
indicating that the status of the specific credit account is
approved and for providing a second signal indicating that the
status of the specific credit account is not approved;
print-out means including an imprint mechanism, said print-out
means normally disposed in an inoperative mode wherein said
print-out mechanism is maintained at a first position and
responsive to the first signal to be disposed in an operative mode
wherein said print-out mechanism may be moved between said first
position and a second position to provide a print-out at said
terminal unit; and
erase means responsive to the return of said print-out mechanism to
said first position for removing the data from said memory means.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention resides in the field of terminal units for
data storage and retrieval systems for transactions involving
credit accounts.
2. Prior Art
Many systems have previously been proposed in which a terminal unit
is provided at a cashier's station (i.e., a point of sale) in a
retail store to permit the cashier to check the credit of a
customer who desires to have a purchase charged to his credit
account. Typically, the account number of the customer and the
amount of the purchase are manually entered into the terminal unit
by the cashier. The terminal unit is connected to a nearby central
record storage facility having a computer which responds to the
data entered by the cashier to retrieve stored information
regarding the status of the designated account and to compare that
information with the newly entered data. The purpose of this type
of system is to apprise the cashier of the condition of the account
of the customer seeking credit before an actual transaction is
completed. The cashier is then in a position to determine whether
credit should be extended to the customer to cover the purchase in
question, or credit should be refused.
The cost of the typical terminal unit used in the prior systems has
been sufficiently great to preclude the installation of a terminal
unit at each cashier's station in a large retail store. The cashier
at a station lacking a terminal unit must call a cashier at a
station having a terminal unit, to institute a check of the
customer's credit before completing the credit transaction. The
result is a loss in the efficient utilization of personnel, in
addition to a slowdown in the speed with which a credit check could
be obtained with a system having a terminal unit at each
station.
Another problem occurring in prior art systems is that the computer
must be on-line before the cashier is permitted to enter data
regarding the transaction at the terminal unit. Otherwise, the
message to the computer will be incomplete and will not evoke the
desired response. This has meant that the cashier must manually
enter data at the expense of valuable computer time, and at the
loss of communication time to other terminal units waiting to
transmit messages to the computer.
A further difficulty with prior art credit inquiry systems is that
many require the cashier to decipher a lengthy stream of encoded
data received in response to an inquiry in order to determine how
to handle the transaction. Such a requirement assumes that the
cashier is sufficiently skilled to perform the task of deciphering
a perhaps complex message rather quickly. Otherwise, the customer
will encounter substantial delay in a credit transaction.
In order to produce a written record of a credit card transaction,
it has been the practice to provide an auxiliary imprinter at the
cashier's station. The auxiliary imprinter is completely distinct
from the terminal unit itself and is merely used to transfer an
inked impression of the embossed characters on the credit card to a
sales slip. Thereafter, the cashier completes the necessary entries
on the sales slip by hand, for the customer's signature. This
practice requires the cashier to perform two separate but related
operations; the first, entering message data into an information
retrieval system, and the second, entering at least some of the
same data onto a printed form. The undesirable duplication of
effort can result in dissatisfaction of the cashier and will result
in delay to the customer.
SUMMARY OF THE INVENTION
The principal object of the present invention is to provide a
terminal unit for use in a credit account investigation and
maintenance system, and which avoids the several disadvantages of
the prior terminal units set forth above.
In describing an exemplary embodiment of the invention, it will be
convenient hereinafter to refer to any input/output device at a
station other than the central station as a "terminal unit."
Moreover, since systems according to the invention are useful to
diverse companies, such as sales organizations, service firms, and
credit investigation agencies, the specific location of any
terminal unit will hereinafter be termed a "remote station,"
regardless of whether it is a point of sale, a point of service, a
credit account desk, or other point. For the same reason, the party
operating the terminal unit at any remote station will hereinafter
be referred to as the "operator," despite the fact that such party
may perform some additional function, such as would a sales clerk,
a cashier, a service representative, a credit manager, and so
forth.
Briefly, a system to record, to retrieve, and to manipulate data in
credit accounts as credit transactions occur includes a
multiplicity of terminal units. Each terminal unit is located at a
remote station relative to a central data processor station. Input
data regarding a credit transaction is manually entered into a
terminal unit to form a message of inquiry for transmission to the
data processor. In response to the message of reply received from
the data processor, the terminal unit produces an appropriate
output. In particular, each terminal unit is provided with visual
indicator means to be energized by and in accordance with the
contents of the reply message, to fully inform the operator how to
proceed with respect to the credit transaction on which the inquiry
is based. Each terminal unit preferably is also provided with means
for producing a record of a completed transaction.
In a specific embodiment of the present invention, the terminal
units are implemented to store input data entered by the operator,
prior to transmission of the data to the data processor. Upon entry
of all of the data required to form an inquiry message, a signal is
generated within the terminal unit. This signal initiates an
attempt to acquire an idle communication channel between the
terminal unit and the central data processor. If the attempt is
successful, a second signal is received from the data processor
over the acquired communication channel. The first signal is
sufficiently long to be present when the second signal is received,
and the concurrence of these two signals at the terminal unit
initiates transmission of the inquiry message. This concurrence
condition is important for two reasons. First, it assumes that no
transmission will occur from the terminal unit if any message data
remains to be entered therein, regardless of the receipt of a
signal from the data processor. Second, it prevents the readout of
message data when no communication channel is available. The second
case is particularly significant where the data storage device
undergoes destructive readout. Moreover, in both cases the message
data must be manually entered before the data processor is on-line.
Valuable time of both the data processor and the communications
network is thereby conserved, permitting utilization of both by
other terminal units while a given terminal unit is being fully
prepared for transmission of an inquiry message.
The data processor responds to an inquiry message from a terminal
unit to assess the status of the credit account pertaining to the
inquiry, and to transmit a coded reply message based on the account
status. The inquiring terminal unit decodes the reply message and,
based on the contents of that message, generates the proper visual
signal for the procedure to be followed by the operator.
Each terminal unit is provided with timer means for producing a
signal to clear the terminal unit and to release its communication
channel with the data processor in the event that no reply message
is received by the terminal unit within a timed interval from the
transmission of the inquiry message. Such operation assures that no
terminal unit will tie up the data processor and a communication
channel waiting for a non-existent reply message. However,
provision is made for the terminal unit to hold a communication
channel where several inquiry messages are to be transmitted in a
succession interrupted only by the replies. The operator may elect
to use this "hold" mode at a busy terminal unit, i.e., a terminal
unit at which a high incidence of credit transactions is
occurring.
An imprinter unit provided in each terminal unit is responsive to
the manual entry of certain message data into storage to
simultaneously position corresponding characters in imprinting
position for producing a printed record of the transaction. If the
reply message from the data processor authorizes completion of the
transaction, a normally locked imprint mechanism associated with
the imprinter unit is automatically unlocked to permit manual
actuation of the mechanism for imprinting a sales slip. The
imprinter unit includes means responsive to the return of the
imprint mechanism to a locked condition to release the
communication channel and to clear the terminal unit. Here again,
if the terminal unit is in a "hold" mode, the communication channel
will not be released despite locking of the imprint mechanism.
Each terminal unit also includes an authorization count display
which is advanced one unit with each authorized transaction
occurring at that terminal unit. A purchase refund switch is also
provided on the terminal unit to permit the operator to select
terminal unit operation appropriate to the type of credit
transaction.
BRIEF DESCRIPTION OF THE DRAWINGS:
The above and other objects, features and advantages of the present
invention will become apparent from a consideration of the detailed
description of a preferred embodiment, in which reference will be
made to the accompanying drawings. In the drawings:
FIG. 1 is a circuit diagram of an overall credit maintenance system
in which the terminal unit of the present invention is used;
FIG. 2 is a perspective view of the cabinet of a preferred
embodiment of the terminal unit, showing an imprinter and various
control keys and switches;
FIG. 3 is a circuit diagram of the terminal unit of FIG. 2;
FIG. 4 is a circuit diagram of a decoding unit used in the terminal
unit of FIGS. 2 and 3;
FIG. 5 is a circuit diagram of a portion of the decoding unit of
FIG. 4;
FIG. 6 is a view of the front face of a typical sales slip on which
transaction data has been imprinted by the terminal unit of FIGS. 2
and 3;
FIG. 7 is a fragmentary side view, partly in phantom, of a latch
switch for use with the imprinter of the terminal unit;
FIG. 8 is a representation of the contents of a message of inquiry
transmitted from a terminal unit;
FIG. 9 is a side view of an embodiment of a slide switch and
linkage for use in the terminal unit; and
FIG. 10 is a flow chart of the operation of a terminal unit.
DESCRIPTION OF THE PREFERRED EMBODIMENT:
Referring to FIG. 1, a system for handling credit transactions
includes a data processor 10 located at a central station. The data
processor includes a computer with a memory unit having adequate
capacity to store the credit account information necessary to
permit the data processor to respond to inquiries regarding the
status of any member's credit account. The inquiries are
transmitted to the data processor from any of a plurality of
terminal units 12 located at remote stations assigned by
organizations authorized to use the system. These remote stations
may be located in several cities, including the same city in which
the data processor 10 is located. Only the local equipment in City
A is shown in any detail in FIG. 1, but it is to be understood that
this equipment is typical of the equipment in City B, City C, and
so forth. Upon receipt of an inquiry from any terminal unit 12,
data processor 10 checks the status of the account which is the
subject of the inquiry and transmits a reply to the inquiring
terminal unit.
A communications network 15 is provided to interconnect the
terminal units 12 and the central data processor 10. Preferably,
the communications network 15 utilizes ordinary telephone lines,
some of which are used for handling relatively low rates of data
transmission, and others of which are used for handling relatively
higher rates of data transmission. In particular, transmission of
data at a low rate from each terminal unit allows a group 14 of
several terminal units to contend for a single local line 16. The
low speed transmission of data over local lines 16 is nevertheless
sufficiently rapid to preclude the tying up of any local line 16 by
only a few terminal units 12 of a group 14 contending for that
line. A supervisory terminal unit 21 is associated with each group
14 and is coupled to the same telephone central office 13 for use
of the same switching equipment.
The low speed data on all local lines 16 in a given geographical
area, such as in an entire city, is ultimately compressed together
i.e., is multiplexed) for transmission at a substantially higher
data rate on a feeder line 18 to the central data processor 10. In
essence, each local line 16 acts as a branch line for one feeder
line 18 which constitutes a trunk line. Multiplexing of data from
several local lines 16 to a trunk line 18 in communications network
15 is performed by a data distribution system 20, in each
geographical area. Each data distribution system 20 also serves to
distribute high speed data from the trunk line 18 to the respective
local lines 16, in the opposite direction of transmission. The
local lines 16 are connected to the data distribution system 20 by
lines 19 from telephone poles 17. Of course, the communications
network 15 may use underground transmission lines, rather than
"open wire" transmission lines, or a combination of both. Moreover,
the communications network may utilize microwave transmission
channels along a part of its route. Specific reference is made to
the use of ordinary telephone lines only because they are readily
available and are relatively inexpensive to lease, in comparison
with some other forms of transmission channels. Each data
distribution system 20 is connected to its respective trunk line 18
via a line from a pole 21a.
Each trunk line 18 serving a multiplicity of remote stations in a
given geographical area is, in turn, coupled to communications
equipment 24 via a line 23 from a pole 22. The communications
equipment 24 is utilized to supply high speed data from the several
trunk lines 18 to the central data processor 10, and to distribute
high speed data from the data processor to the appropriate trunk
lines. Accordingly, communications equipment 24 may correspond
quite closely to a data distribution system 20 in data multiplexing
and data distributing performance and implementation. In addition,
the communications equipment includes transmitting and receiving
apparatus for communicating with the data processor 10.
Further details of the system of FIG. 1, other than details of the
terminal unit 12, are not essential to a complete disclosure of the
present invention and to a thorough understanding of the invention.
Accordingly, no further description of the system will be presented
here. The interested reader is referred to the co-pending United
States patent application of R. J. Deschenes, et al., Ser. No.
18,665, entitled "System For Maintaining the Status of Credit
Accounts," filed Mar. 11, 1970, for system details.
Referring to FIGS. 2 and 3, showing the cabinet and the circuitry,
respectively, of an embodiment of a terminal unit 12 according to
the present invention, each terminal unit is preferably implemented
to accept a credit card of an individual or of an organization
involved in a particular credit transaction. It is to be
emphasized, however, that it is neither essential to the overall
system in general, nor to the terminal unit in particular, that a
credit card be utilized during the course of the transaction. In
the terminal unit of FIGS. 2 and 3, the customer's name and
identification number (i.e., account number) typically embossed on
the credit card are conveniently imprinted by a cooperating
imprinting mechanism on a sales slip which will constitute a record
of the transaction. If the terminal unit is to be used in credit
transactions where credit cards are not required, the imprinting
mechanism may obviously be dispensed with in the design of the
unit.
With specific reference now to FIG. 2, cabinet 100 of a typical
terminal unit 12 is provided with several keys and switches to
permit the operator to enter data pertaining to the transaction
into the terminal unit, for ultimate transmission to the data
processor 10. A keyboard 102 having ten digit keys ranging from 0
to 9, and having two auxiliary keys labeled "S" and "R" which will
be discussed presently, is provided on a front surface 103 of
cabinet 100. The ten digit keys may be arranged in any convenient
manner to make them readily accessible and efficiently used by the
operator. For example, these keys may be arranged in the same order
as the buttons on a standard telephone set pushbutton dial, but
that arrangement is obviously not essential. The digit keys on
keyboard 103 are used by the operator to manually enter the account
number of the customer into storage in the terminal unit, as a
portion of the inquiry message.
Also provided on the front surface 103 of cabinet 100 for easy
access to the operator is a set of slide switches 105. Each of
slide switches 105 can be moved forward or backward in its
respective channel 106, adjacent which is provided a column of
digits 107. The slide switches 105 are used to enter the amount of
the purchase, in dollars and cents, into a message format to be
transmitted to the data processor. Furthermore, slide switches 105
are coupled to a set of wheels 115 bearing raised indicia in units
of purchased amount, at the sales slip imprinting region 126 of the
terminal unit. As will be discussed in greater detail presently,
the slide switches 105 are respectively linked to the raised
character wheels 115 to advance the wheels to an imprinting
position corresponding to the amount of the purchase, upon
appropriate positioning of the knobs of switches 105.
A purchase/refund (P/R) switch 120 is also provided on front
surface 103 of cabinet 100, for presetting the terminal unit for
use with the proper transaction, that is, to the P position of
switch 120 for a purchase transaction and to the R position of the
switch for a refund transaction. Switch 120 is normally locked in
the P position to prevent inadvertent authorization and recordation
of a refund when in fact a purchase transaction is occurring, and
to prevent indiscriminate authorization of a refund by the
operator. The need for use of a key to operate the P/R switch is
itself sufficiently informative to the operator to prevent
inadvertent errors or improper use. Nevertheless, it may be
desirable to provide only supervisory personnel with a key by which
to operate the P/R switch 120. Depending upon the position of that
switch, a character indicative of a purchase transaction or a
refund transaction is automatically entered into the message format
for transmission from the terminal unit.
A normal/hold (N/H) switch 122 consisting of a two-position switch
is disposed on front surface 103 of cabinet 100 to permit the
operator to select either a normal operation or a hold operation.
In the normal operation, the local line 16 which has been acquired
by the terminal unit 12 for transmission of an inquiry to the
central data processor is released by the terminal unit virtually
immediately following receipt of a reply message from the data
processor. In other words, the terminal unit must "hang up" in
order to terminate its connection to the local line 16 so that the
line is available to other terminal units, and this is normally
accomplished after each two-way communication. In the hold
operation, the connection with local line 16 is maintained by the
terminal unit for continued communication with the central data
processor for as long as the N/H switch of that terminal unit is in
the "hold" position. The hold operation is usually selected by the
operator when several messages are to be transmitted in succession
to check on the status of several accounts in view of the
occurrence of credit transactions involving those accounts. A
character representative of the position of the N/H switch 122 is
automatically entered at the terminal unit into the message format
for any given transaction.
A set of lamps 125 is positioned on front surface 103 of cabinet
100 to be readily observable to the operator. The lamps are
preferably color coded, and are also provided with appropriate
indicia on their respective caps, to render them distinctive when
lit. The lamps are used as guide indicators to inform the operator
how to proceed with respect to a given transaction. The content of
a reply message in response to an inquiry regarding the given
transaction is determinative of which of the lamps 125 is
energized, and thereby, what procedure is to be followed by the
operator.
A credit card platen 128 and an authorized user identification
platen 129 are provided within the sales slip imprint region 126 of
cabinet 100. These two platens, along with a boss 130 and two sets
of raised character wheels 115, 132 define a substantially level
surface over which the roller (not shown) of an imprint mechanism
131 is movable. The two sets of raised character wheels in the
sales slip imprint region 126 are for imprinting the dollar amount
and the data, respectively, of the transaction on the sales slip.
The raised characters on the sets of wheels 115, 132 and on platen
129, and the embossed characters on a credit card placed on platen
128 are all positioned in the plane of the aforementioned level
surface to bear against the sales slip at predetermined regions
thereof as the roller within imprint mechanism 131 is moved across
imprint region 126. The imprint mechanism 131 is restricted to
movement over the imprint region by attachment to guide wheels 136
at both sides of the cabinet. The guide wheels roll within channels
137 in the cabinet below and at both sides of the imprint
region.
As will presently be discussed in further detail, imprinter 131 has
an associated latch to prevent its movement from a "home" position,
at the extreme left-hand end of imprint region 126 as viewed in
FIG. 2, unless the reply message authorizes completion of the
transaction. In the latter event, the imprinter is unlatched for
manual movement by the operator. When returned to the "home"
position, the imprinter is automatically latched.
With reference now to FIG. 3, the internal circuitry of a typical
terminal unit 12 includes an internal memory 150. The internal
memory is supplied with input data to be stored in accordance with
the operation of keys and switches by the operator for a given
transaction. The storage capacity of the internal memory 150 should
be sufficient to hold all the data required for a complete inquiry
message pertaining to the given transaction. This required data
includes, in addition to that manually entered by the operator,
several permanently stored items of information. In particular, the
permanently stored information consists of characters designating
the type and identity of the terminal unit, and designating the
start and the end of a message. When the data pertaining to a
specific transaction has been entered into internal memory 150, the
memory contains a complete inquiry message for that transaction,
because the permanently stored characters remain in their
appropriate locations for continual proper positioning in any
inquiry message.
The operator then depresses a send ("S") key 152 on keyboard 102 in
preparation for transferring the inquiry message to the central
data processor. In response to actuation of send key 152, a latch
mechanism 163 operates to lock slide switches 105 in position to
prevent any movement of those switches during actual transmission
of an inquiry message. In addition to energizing the slide switch
latch mechanism, actuation of send key 152 supplies a signal to
initiate the operation of an automatic dialer 154. The dialer 154
serves to establish a communication channel between the terminal
unit and the central data processor, as is necessary before the
inquiry message can be transmitted. This is accomplished upon
acquisition of the appropriate local line 16 by the terminal
unit.
Each local line 16 is assigned a unique "telephone" number to
determine whether the line is busy, i.e., is in use by another
terminal unit sharing that local line, or is idle, i.e., is
available. It is preferable that the "telephone" number of the
appropriate local line 16 be "dialed" by an automatic dialer upon
actuation of send key 152. The automatic dialer 154 responds to
actuation of the send key to transmit a series of pulses
representing the desired number to a telephone coupler 157
connected to local line 16. If line 16 is idle, a connection is
completed with the terminal unit that dialed the number, and the
line is thereafter unavailable to other terminal units until the
acquiring terminal unit releases the connection (i.e., "hangs
up").
Once the connection has been established between the terminal unit
and local line 16, a carrier tone is transmitted to the terminal
unit from the data processor via that local line. The carrier tone
passes through coupler 157 and modem 155 and is thereupon detected
by a carrier detection circuit 162. The carrier detection circuit
then supplies a signal to one input line of a two-input AND gate
165. The second input of AND gate 165 is energized by a signal from
the actuated send key 152. In essence, the send signal is
indicative of the completion of entry of data into internal memory
150, and the length of this signal should be sufficient that it is
present when the carrier tone is detected. Hence, the input
condition of the AND gate 165 is satisfied to cause a "start"
signal to be supplied by the AND gate to a scanner 167. The scanner
is thereby activated to access message data from the internal
memory 150 in the proper inquiry message format.
Accordingly, an inquiry message is transmitted from a terminal unit
only upon concurrence of the send signal and the carrier tone, and
this occurs after the data for a complete inquiry message has been
manually entered by the operator. Such operation insures that no
portion of the message will be lost by partial transmission prior
to establishment of a connection to the central data processor.
Moreover, this operation further insures that the on-line time of
the central data processor for a given terminal unit is minimized,
because there is no manual entry of data by an operator while the
data processor is on-line.
Upon detection of carrier tone, detector 162 supplies an energizing
voltage to an "on-line" lamp 160, in addition to energizing one
input lead of AND gate 165. The lighting of lamp 160 informs the
terminal unit operator that local line 16 has been acquired, and
that the inquiry message is being transmitted.
It may happen that one of the other terminal units is using line 16
at the time the number for that line is "dialed" by automatic
dialer 154. In that event, a busy signal is encountered and the
connection is not completed. The lack of carrier tone at detector
162 prevents the energization of on-line lamp 160, thereby
informing the operator that local line 16 is presently unavailable.
The operator may then simply wait a few seconds and again depress
send key 152 to repeat the attempt to establish the communication
channel with the central data processor. The number of terminal
units connected to a single local line, and the average length of
time for a single transaction communication between any given
terminal unit and the central data processor, are taken into
consideration prior to installing the system to insure that any
given terminal unit will have access to its local line 16 within a
matter of only a few seconds. It should be noted that instead of
automatic dialer 154, the terminal unit may have an associated
telephone handset (not shown) by which the operator can manually
"dial" the number of local line 16.
The information scanner 167 is coupled to internal memory 150 to
access the stored data therefrom in a predetermined sequence in
serial binary format to form the inquiry message. This inquiry
message is transmitted by the scanner through modem 155 and into
local line 16 for transmission to the central data processor via
communications network 15.
The operation involving scanner 167 assumes that the message
information is stored in internal memory 150 in parallel storage
elements, and that the scanner comprises a commutator or equivalent
device. Alternatively, however, internal memory 150 may comprise a
shift register into which the message data is entered in specific
bit locations upon actuation of the appropriate keys and switches
by the operator. In that event, an output from AND gate 165 may
conveniently be used to start a shift pulse generator (not shown),
which replaces scanner 167, for shifting out the contents of
internal memory 150 in serial binary format directly to modem
155.
The output of AND gate 165 also supplies a "start" signal to timer
169. The timer is implemented to generate an output signal at the
conclusion of a predetermined timed interval from the starting of
the timer. If a "valid" reply message is not received by terminal
unit 12 from the central data processor within this timed interval,
the timer supplies a signal to OR gates 175 and 177. In response to
an input signal on any of its respective input leads, OR gate 175
produces an output to clear internal memory 150 of all temporarily
stored message information and to release latch 163 to unlock all
switches and keys controlled by that latch, and OR gate 177
produces an output to release local line 16.
A "valid" reply message is any message which is detected by the
terminal unit to be free of transmission errors upon receipt from
the data processor. In order to detect the presence of an error in
a reply message, the message may contain any standard error
detecting code for which suitable error detection apparatus is
provided at the terminal unit. A reply decode logic circuit 170 is
implemented to detect such error and to indicate its presence in
the reply message, but is not adapted to correct an error. The
reply message is supplied to the reply decode logic circuit via the
carrier detection circuit 162. If the reply message is valid, the
reply decode logic circuit produces a signal to turn off timer 169
and to "hang up" the terminal unit (via N/H switch 122, if in the
"normal" position). In addition, the reply decode logic circuit
decodes the message to energize an appropriate one of the
procedural guide lamps 125 on the front panel 103 of cabinet 100
(FIG. 2).
If the reply message is not valid, the timer is allowed to conclude
its timed interval to supply an output signal to OR gate 175, and
thereby to restore the terminal unit to the condition prevailing
prior to the entry of inquiry message data. The output signal of
the timer is also applied as a momentary "release" signal to
another OR gate 177 to "hang up" the connection with local line 16.
This precludes a tie-up of valuable communications network time. An
error lamp 171 is energized by the output signal of timer 169 to
inform the operator that the inquiry message data must be
re-entered into internal memory 150 and that a communications
channel must be re-acquired with the central data processor, if
further inquiry is to be made regarding the status of the credit
account involved in the transaction.
Upon detection of a valid reply message from the central data
processor 10, the reply decode logic circuit 170 decodes the
message to produce various visual indications for imparting
procedural information to the operator. The particular indication
depends upon the status of the account, and upon any limitations
placed upon the account, as recorded in the central data processor.
In each instance, the indication is manifested by the energization
of an appropriate procecural guide lamp 125. If the contents of the
reply message authorize completion of the transaction by the
operator, an "authorization" indication is manifested by the
energization of an "OK" lamp 172. If the reply message rejects
completion of the transaction, the operator is so informed by an
"unauthorized" indication, manifested by energization of a "NO"
lamp 173. The latter indication should occur where, for example,
the credit check at the central data processor reveals that the
customer is a poor credit risk, or that the identified account
number belongs to a customer who has reported the loss of his
credit card. If the reply message conveys the information that the
state of the credit account makes completion of the transaction
questionable, the operator is given the appropriate indication by
the energization of a lamp 174 bearing a question mark (?). Such an
indication will occur, for example, where the amount of a specific
purchase exceeds the customer's authorized credit limit, or where
the balance due on the credit account is ordinarily paid promptly
but at the time of this inquiry is overdue. The supervisory
terminal unit 21 at the audit station for the terminal unit 12 that
transmitted the inquiry may be signalled when the "questionable"
indication occurs, to indicate the need for assistance at the
latter terminal unit. The replay decode logic circuit 170 may also
be implemented to energize the "error" lamp 174 in place of
energization of that lamp by timer 169.
Preferably, in addition to bearing appropriate indicia, each of the
procedural guide lamps has a distinct and different color from the
others. This permits the operator to readily distinguish between
lamps, and thus between the procedural information that they
relate. The lamps are conveniently color coded to correspond to
everyday warning signals. For example, "OK" lamp 172 may be green,
error lamp 171 may be yellow or amber, and "NO" lamp 173 may be red
to correspond to the usual meanings "Proceed", "Caution", and
"Stop", respectively, found in everyday situations. The remaining
lamps consisting of "?" lamp 174 and on-line lamp 160 may be blue
and white, respectively. However, it will be understood that other
colors may be employed for lamps 125, if desired. Again, the
important consideration is the provision of a set of visual
indicators on the terminal unit in full view of the operator, to
apprise the operator of the establishment of a connection with the
central data processor, and thereafter, the procedure to be
followed with regard to the transaction on which the original
inquiry was based.
Referring for the moment to FIGS. 4 and 5, the reply decode logic
circuit 170 may have the configuration shown in FIG. 4, and may
include a procedure decoder logic circuit 185 having the
configuration shown in FIG. 5. The reply message is initially
examined in a validity detector 180 to determine whether the reply
message is valid. The validity detector may make this
determination, for example, by checking one or more parity bits in
the reply message. If the message is valid it is passed by validity
detector 180 with a preceding additional pulse for turning off
timer 169. Assuming that the reply message is in serial binary
format, it is fed into a register 183 for temporary storage.
Register 183 responds to an end-of-message (EOM) character in the
reply message to read out its contents in parallel format to the
procedure decoder logic circuit 185. The latter circuit decodes the
message and energizes the appropriate procedural indicator lamp
125.
A simplified diagram of procedural decoder logic circuit 185 is
shown in FIG. 5. The procedural decoder logic includes four AND
gates 186, 187, 188 and 189, each having three input terminals and
each connected for parallel receipt of three bits. The reply
message need only contain two procedural information bits B.sub.1
and B.sub.2 to provide any of four possible outputs from reply
decode logic circuit 170. Clearly, two bits are necessary and
sufficient to provide four distinct and different binary value
combinations. The third input bit, T, is the previously mentioned
validity information pulse added to the reply message by validity
detector 180 only when a valid message has in fact been received.
If reply decode logic circuit 170, rather than timer 169, is to
energize error lamp 171, one of the four AND gates may either be
deleted or replaced by a single input OR gate (not shown) for
energization of the error lamp by pulse T. Alternatively, the
fourth AND gate may be arranged to receive identical bits on its
three input leads for energization of the error lamp. The latter
configuration is shown in FIG. 5.
Each of AND gates 186, 187, 188 and 189 therefore receives a
validity bit T and two message bits B.sub.1 and B.sub.2. The AND
gates are arranged in conventional decoder circuit form to provide
one of four possible outputs depending upon which of the four
combinations of the two message bits is present in the reply
message. Inverters 190 are provided in some of the input leads in
the AND gates as necessary to take care of "0" bits. One and only
one of the AND gates can have all of its input leads energized at
any given instant of time. The output lead of each gate is
connected to a respective one of the procedural indicator lamps 125
to provide an energizing voltage to the appropriate lamp.
Returning now to FIG. 3, the energizing voltage generated by reply
decode logic circuit 170 for any of the procedural indication lamps
171, 173, and 174 is also supplied in parallel to an associated
input lead of OR gate 175. As described earlier, the presence of a
voltage on any of its input leads causes the OR gate to produce an
output voltage which clears internal memory 150 of all temporary
data, and unlatches all switches which had been latched by slide
switch latch 163. The remaining input leads of OR gate 175 are
respectively connected to the output lead of timer 169, noted
earlier, and to a reset switch 165 and to an imprinter latch switch
166.
Energization voltage applied to "OK" lamp 172 by reply decode logic
circuit 170 is also applied in parallel to imprinter latching
switch 166 and to authorization counter 133. Thus, when the reply
message authorizes completion of the transaction, the "OK" lamp 172
is lighted to so inform the terminal unit operator, and
simultaneously with the energization of the "OK" lamp, the
authorization counter 133 is advanced one unit and the imprint
mechanism 131 is released from its "home" position. The imprint
mechanism can then be manually moved across the sales slip imprint
region 126 (FIG. 2) to produce a record of the completed
transaction. In view of the fact that when a transaction is
authorized to be completed the credit account is automatically
updated, such a record need not be provided for the store unless a
copy is desired as a means to check the account record at the
central station. However, the customer will generally be provided
with a sales slip for his own records.
A typical form of sales slip on which a record of the credit
transaction is imprinted by terminal unit 12 is shown in FIG. 6. A
slip 200 having blank spaces in which the appropriate information
is to be printed is placed within imprint region 126, to overlie
the customer's credit card and the several platens and character
wheels. As the imprint mechanism 131 is moved across the slip,
pressure is exerted against all of the embossed and raised
characters beneath the slip to produce corresponding visible
impressions on the slip. In the specimen of FIG. 6, the impressions
include the customer's name and credit account number, in space
202, and the store 203, the date 204, and the amount 205 of the
purchase.
After removing the imprinted sales slip from the imprint region 126
of the terminal unit, the operator may write in the authorization
number 206 of the transaction and the identity and the cost of each
item 210, if this information was not entered previously. The slip
may then be handed to the customer for signature on line 212. If
the slip is a multisheet document, one copy is given to the
customer and the remaining copies are retained by the store.
After the imprint mechanism 131 has been cycled, i.e., to record
the transaction, it must be returned to its "home" position. In
this regard, it will be observed from FIG. 3 that the energization
of "OK" lamp 172 is not accompanied by the energization of an input
lead of OR gate 175, as occurs for the energization of each of
lamps 171, 173, and 174. Hence, there is no automatic clearing of
the internal memory and releasing of all switches and keys. No
further credit transactions can be handled by the terminal unit
until the memory and the switches are cleared. For the latter
purpose, imprinter latch switch 166 is implemented to generate a
"one-shot" pulse when the imprint mechanism is returned to its
"home" position and is locked in place by switch 166. This pulse is
applied to OR gate 175 to clear the memory and the switches in
preparation for entry of an inquiry message consonant with the next
transaction.
A suitable embodiment of the imprinter latching switch 166 is shown
in FIG. 7. A solenoid 220 is mounted by brackets (not shown) within
cabinet 100, beneath one side of imprint mechanism 131. An armature
221 projects from the coil housing of solenoid 220 and is pivotally
fastened at one end 223 to a catch (i.e., a hook) 225. The catch
225 is also pivotally fastened to a fixed bracket 228 mounted on
the upper panel of cabinet 100.
When the solenoid is non-energized, the normal projecting length of
armature 221 is such that catch 225 is hooked over a lip 230 of
imprint mechanism 131. This serves to prevent movement of the
imprint mechanism to the right, as viewed in FIGS. 2 and 7, away
from the "home" position. When the solenoid is energized, by a
signal from the reply decode logic circuit 170 applied to the
solenoid coil, the armature 221 is retracted within the solenoid
housing. This causes catch 225 to pivot in the clockwise direction
about its pivot point with bracket 228, thereby disengaging from
lip 230 and releasing the imprint mechanism.
A spring-loaded microswitch 233 is mounted on an arm 235 to exert
pressure against the imprint mechanism. Hence, when latch switch
166 is actuated to the release position, the imprint mechanism is
forced clear of the "home" position to prevent recapture by catch
225 after de-energization of the solenoid. Microswitch 233 is
mounted relative to the imprint mechanism 131 so that a surface of
the imprint mechanism bears against an actuating button of the
microswitch when the mechanism is in the "home" position. The
microswitch is a one-shot switch in that it generates one and only
one output pulse each time the actuating button is depressed.
Accordingly, when the imprint mechanism is returned to the "home"
position, the microswitch is actuated to produce the pulse which is
applied to OR gate 175 (FIG. 3).
The provision of a structure and an operational mode requiring
manual movement of the imprint mechanism 131 has several advantages
over automatic actuation of the imprint mechanism. First, the
transaction record will not be consummated until the operator
places the customer's credit card in position on platen 128 (if a
credit card is required for the transaction), and optionally checks
the date wheels 132 and the authorization counter display 133,
because movement of the imprint mechanism is controlled by the
operator. If automatic movement were provided, and the credit card
were not in position on platen 128, the imprint mechanism would
nevertheless go through its cycle. Second, manual operation gives
the operator an opportunity to seek supervisory assistance, should
the need arise, prior to restoring the terminal unit to a fully
cleared condition. Third, manual operation of the imprint mechanism
does not require bulky motors and linkages within the terminal unit
cabinet, as automatic operation would. Furthermore, the latching of
the imprint mechanism upon return to its "home" position assures
that there will not be any use of the mechanism to imprint a sales
slip unless authorization is given in a reply message to complete a
transaction.
Returning again to FIG. 3, the only remaining input lead of OR gate
175 is connected to reset key 165, located on keyboard 102 of
cabinet 100 for ready access by the operator. When the reset key is
actuated, it energizes that input lead to cause the OR gates 175
and 177 to provide the memory clearing, switch unlocking, and local
line releasing functions, respectively, previously described. This
manual reset operation may be performed at any time prior to
initiation of the sending sequence, that is, at any time before
actuation of send key 152 effects the acquisition of local line 16.
Thereafter, carrier detection circuit 162 responds to the almost
instantaneous reception of carrier tone from the central station to
supply an energizing signal to an inhibit circuit 178 in the reset
signal path. Accordingly, reset key 165 can no longer be used to
initiate the aforementioned functions until the carrier tone is
removed. This arrangement assures that the operator will not
inadvertently interrupt the sequence by depressing the reset key
after a communication channel has been established with the data
processor.
When N/H switch 122 is in the "normal" position, as shown in FIG.
3, the terminal unit releases the "connection" with local line 16
via coupler 157 whenever reply decode logic circuit 170 produces an
output signal. This is accomplished by connecting the output lead
of circuit 170 to an input lead of OR gate 177. The latter OR gate
supplies a "hang up" signal to telephone coupler 157 when any one
or more of its inputs are energized. In addition to the input from
the reply decode logic circuit, OR gate 177 receives inputs from a
"loss of carrier" (i.e., absence of carrier tone) output lead of
detection circuit 162, from timer 169, and from reset key 165. The
"hang up" signal of OR gate 177, or a signal derived therefrom upon
release of local line 16, is sensed by the communications equipment
24 at the central station to "hang up" at that end. It is only when
both ends of the communication channel are released that the
channel itself is completely released.
A typical format for an inquiry message transmitted from a terminal
unit 12 is shown in FIG. 8. A total of 29 characters appears in the
inquiry message, in the example shown in FIG. 8. The first
character in the message identifies the start of the message and is
of appropriate form to uniquely identify the source of the message
as a unit authorized to operate in the system. The purpose of using
such a unique start character is to preclude use of the system by
unauthorized equipment. It is possible, for example, that a
standard teletype unit might have access to a local line, by
surreptitious connection thereto or by improper wiring. Since an
unauthorized teletype unit is not capable of generating the unique
start character, however, any message transmitted therefrom would
be ignored by the central data processor. Alternatively, the
central data processor may be implemented to sense the appearance
of an improper start character and thereupon to generate an
appropriate signal to advise a central data processor operator of
the location of the local line on which that message appeared.
Appropriate action may then be taken to remove the offending unit
from the system.
The second character in the inquiry message identifies the type of
terminal unit from which the message was transmitted, if several
different types of terminal units are usable in the system. The
system may, for example, be implemented to operate basically as a
credit account status maintenance system, as described herein, but
may also have auxiliary use as a fire or burglar alarm system. That
is to say, the central data processor may be implemented or
programmed to recognize the specific terminal type from which a
message is received, and to generate a signal, such as an alarm, at
the central station on the basis that a transmission from that type
of terminal unit is itself indicative of the existence of an alarm
condition.
Message characters three through eight, inclusive, identify the
number of the terminal unit. Each terminal unit has a distinct and
different identification number from the other terminal units.
Each of the message characters thus far described is permanently
stored in internal memory 150, because the signification of the
start of a message, the terminal type, and the terminal
identification number will remain fixed regardless of the
particular transaction. The last character in the inquiry message,
identifying the end-of-message (EOM) is also fixed and, hence, is
permanently stored in memory 150. The remaining message characters
may vary from transaction to transaction and are therefore entered
into temporary storage in memory 150 by the operator.
In particular, the ninth through the fifteenth characters,
inclusive, identify the dollar amount of the purchase. These
characters are entered by appropriate positioning of the slide
switches 105 on the front panel of terminal unit cabinet 100 (FIG.
2). The slide switches are also linked to the set of imprint wheels
115 in the sales slip imprinting region 126. A suitable embodiment
of the slide switches and the linkage for accomplishing this dual
function will be described presently.
Message characters 16 through 25, inclusive, are entered by means
of the digit keys on keyboard 102 to identify the credit account
identification number. This is identical to the credit card number
where the credit organization (e.g., American Express, Master
Charge, etc.) employs credit cards for the purpose of identifying
members. One or two of the characters may also be used to identify
the particular credit organization to which the customer belongs
(e.g., AX for American Express, MC for Master Charge, and so
forth).
The twenty-sixth and twenty-seventh characters are the
purchase/refund indication and normal/hold indication,
respectively. These characters are automatically entered for a
particular transaction in accordance with the positions of switches
120 and 122, respectively, adjacent keyboard 102 on front panel
103.
The twenty-eighth character in the message, immediately preceding
the EOM character, is a check character which is used as part of an
error detection code. The check character is determined by counting
the number of binary "1's " (or, alternatively, the number of
binary "0's " ) in the preceding 27 characters of the message, and
identifies the total. This is accomplished by a check character
counter 193 (FIG. 3) which is responsive to the message character
bits emanating from scanner 167 to count the "1's" therein and to
supply the total as an input to the scanner for entry in the
twenty-eighth character location. When the inquiry message is
received at the data processor, the "1's" in the first 27
characters are again counted and the total must tally with the
check character. Otherwise, an error is indicated.
The error detection code may also include a parity bit which
accompanies each character and indicates whether the binary code
for that character has an even number of "1's" (including none), or
an odd number. For example, the parity bit is "0" for an even
number, and is "1" for an odd number. This may be entered into each
character by any known parity bit generation technique.
The table below contains one example of a suitable binary code (and
appropriate parity bit) for each character in an inquiry message
other than the check character. The check character will always be
a number that depends on the binary composition of the preceding
characters in the message. Obviously, a minimum of four binary bits
is both necessary and sufficient to encode the 16 distinct and
different characters which may be used in an inquiry message in
this example.
---------------------------------------------------------------------------
TABLE 1
Character Parity Binary Code 0 0 0000 1 1 0001 2 1 0010 3 1 0100 4
0 1001 5 0 0011 6 0 0110 7 1 1101 8 0 1010 9 0 0101 End of Message
1 1011 Start of Message 1 0111 Purchase 0 1111 Refund 1 1110 Hold 0
1100 Normal 1 1000
__________________________________________________________________________
It will be observed from the Table that the code for characters 0-9
is non-standard. However, any suitable digital code may be used.
The reason for preferred use of the code of Table 1 is the ease of
constructing the slide switches 105 and their respective linkages
to implement this code in comparison to, say, the American Standard
Code for Information Interchange (ASCII). Referring to FIG. 9, the
linkage associated with each slide switch 105 includes a rack 108
having a series of protuberances 110 uniformly spaced apart
adjacent one end of the rack. These protuberances mesh with the
teeth 111 of a circular gear 112 journalled into a concentric
imprint wheel 115 of the set of dollar amount wheels in the sales
slip imprint region. Accordingly, as switch 105 is moved within its
respective slot 106 for positioning adjacent a selected numeral in
the adjacent column 107 (FIG. 2), wheel 116 is rotated through an
appropriate angle to position the same raised numeral thereon in
imprinting position.
Rack 108 also has a plurality of slots 116 cut therein to define
non-uniformly spaced projecting elements 117. A read head 118
having uniformly spaced sensing elements 119 thereon is fixed
relative to the movable slide switch 105. When the slide switch is
positioned at the 0 numeral in column 107 the sensing elements 119
of read head 118 are not in contact with any projecting element 117
of rack 108. Hence, none of the four output bit leads associated
with respective ones of sensing elements 119 has an output therein.
This corresponds to the condition of 0000 as the binary code for
the decimal numeral 0 in the above Table. The slots 116 are cut in
rack 108 so that projecting elements 117 are positioned to contact
sensing elements 119 in accordance with the remainder of the binary
code for characters 0-9 shown in the Table. Thus, as the slide
switch is moved to a numeral in column 107, the projecting elements
117 contact sensing elements 119 to produce the binary code for
that numeral on the four output bit leads. These leads are
connected to appropriate storage locations in internal memory
150.
The operation of the terminal unit in the overall system should be
quite clear from the foregoing description. However, a brief
description of the procedure followed at a terminal unit 12 for a
transaction will now be described, for the sake of completeness.
Concurrent reference is made to the flow chart of FIG. 10. The
customer initiates the transaction by presenting his proposed
purchases and his credit card to the terminal unit operator. The
operator places the credit card on platen 128 and proceeds to set
all switches and keys of the terminal unit to enter the data
regarding the transaction into internal memory 150. The operator
then depresses the send key to actuate the automatic dialer and
thereby to acquire local line 16 provided the line is not busy. If
it is busy there will be no lighting of the on-line lamp 16, and
the operator must repeat the attempt to acquire the local line. If
there is no response on repeated attempts, line failure is
indicated. When the local line is "captured" a communication
channel is established with the central data processor, as
indicated by the energization of the on-line lamp. The inquiry
message is automatically transmitted to the data processor in
response to concurrence of the send signal and the received carrier
tone.
The timer 169 is started at virtually the same instant that the
data in memory 150 is scanned. If a reply is received from the data
processor within the timed interval set by timer 169 it is checked
for validity to stop the timer. Otherwise, the timer energizes
error lamp 171. The reply message is decoded to energize an
appropriate one of the procedural guide lamps. If an
"authorization" indication is manifested, the imprint mechanism is
released to permit manual imprinting of a sales slip. If any
procedural lamps are energized, the terminal unit automatically
hangs up.
It should be apparent that the terminal unit of the present
invention need not be restricted to use in a system involving
investigation of credit transactions. Rather, the same or a
substantially similar terminal unit may be employed in any data
communication system where the accessing of data stored at a
central station is initiated in response to an inquiry from a
remote station.
Accordingly, while a specific preferred embodiment of the invention
has been described herein, it will be apparent that variations and
modifications of the invention will occur to those of ordinary
skill in the art from a consideration of the foregoing description.
It is therefore desired that the present invention be limited only
by the appended claims.
The invention shown in FIG. 9 is disclosed and claimed in the
copending application of Thomas E. Johnson, entitled "Slide Switch
Encoder," Ser. No. 20,648, filed Mar. 18, 1970, and assigned to the
same assignee as is the present invention.
* * * * *